“The massive polka-dotted fish roam the world’s warm oceans as solitary creatures. But they occasionally gather in large groups, or aggregations, to feast on everything from plankton to fish eggs. As the aggregation sites have become known, tourists have flocked to them, with tour operators from Mexico to the Maldives selling opportunities to swim “with the world’s biggest shark.” The slow-moving whale sharks are filter-feeders and pose no danger to humans. They are found in all of the world’s temperate seas, though scientists are unsure how many exist, where they breed or where they give birth.

‘Suddenly everyone has this on their bucket list,” said Brent Stewart, a scientist at San Diego’s Hubbs-SeaWorld Research Institute, who has studied whale sharks in half a dozen countries. “People are willing to pay money for this kind of eco-tourism, and now you see these unintended consequences. We have seen a frenzy in all these areas.'”